Limiting fabric standards
Contents |
[edit] Introduction
The building regulations require that reasonable provision be made to limit heat gains and losses through the fabric of new buildings and works to existing buildings. The approved documents to the buildings regulations set out the limiting standards for the properties of the fabric elements of the building.
[edit] L1A, new dwellings, 2013 edition
| Roof | 0.2 W/(m^2K) |
| Wall | 0.3 W/(m^2K) |
| Floor | 0.25 W/(m^2K) |
| Party wall | 0.2 W/(m^2K) |
| Swimming pool basin | 0.25 W/(m^2K) |
| Windows, roof windows, glazed roof-lights, curtain walling and pedestrian doors | 2.0 W/(m^2K) |
| Air permeability | 10.0 m^3/(h.m^2) at 50 Pa |
[edit] L2A, new buildings other than dwellings, 2013 edition
| Roof | 0.25 W/(m^2K) |
| Wall | 0.35 W/(m^2K) |
| Floor | 0.25 W/(m^2K) |
| Swimming pool basin | 0.25 W/(m^2K) |
| Windows, roof windows, roof-lights, curtain walling and pedestrian doors | 2.2 W/(m^2K) |
| Vehicle access and similar large doors | 1.5 W/(m^2K) |
| High-usage entrance doors | 3.5 W/(m^2K) |
| Roof ventilators (inc. smoke vents) | 3.5 W/(m^2K) |
| Air permeability | 10.0 m^3/(h.m^2) at 50 Pa |
[edit] L1B and L2B, existing dwellings and existing buildings other than dwellings, 2010 editions
| New thermal elements | Retained thermal elements | |
| Wall | 0.28 W/(m^2K) | |
| Pitched roof – insulation at ceiling level | 0.16 W/(m^2K) | 0.16 W/(m^2K) |
| Pitched roof – insulation at rafter level | 0.18 W/(m^2K) | 0.18 W/(m^2K) |
| Flat roof or roof with integral insulation | 0.18 W/(m^2K) | 0.18 W/(m^2K) |
| Floors | 0.22 W/(m^2K) | 0.25 W/(m^2K) |
| Swimming Pool basin | 0.25 W/(m^2K) | |
| Wall – cavity insulation | 0.55 W/(m^2K) | |
| Wall – external or internal insulation | 0.30 W/(m^2K) |
NB Approved Document C gives limiting values for individual elements to minimise the risk of condensation.
[edit] Related articles on Designing Buildings Wiki
- 2013 changes to the approved documents for part L of the building regulations
- Approved documents.
- Building Regulations.
- PA ratio.
- Part L.
- U-value.
[edit] External references
- Approved Document L1A: Conservation of fuel and power in new dwellings, 2013 edition.
- Approved Document L2A: Conservation of fuel and power in new buildings other than dwellings, 2013 edition.
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